In a known fashion, a dispensing nozzle comprises a rigid body in which a liquid dispensing channel is formed. In order to limit contact between the external air and the liquid stationary in the dispensing channel, in particular to avoid drying and/or degradation of said liquid over time, the process of equipping the nozzles with devices for reversible closure of the orifice downstream of the dispensing channel is known.
In particular, such devices can be formed from an elastically deformable sleeve on which there is formed a lip that can be moved by application of the dispensing pressure on it. Reversible closure can then be obtained by disposing the sleeve around the rigid body, with said lip in sealed contact with the downstream orifice, the movement of said lip opening said orifice.
However, so that the lip can be moved with respect to the rigid body, the sleeve must be disposed in a non-adhering fashion around the rigid body. Problems of seal between the sleeve and the rigid body, of mechanical strength of said sleeve on the body and of adjusting the contact pressure of the lip on the downstream orifice are then posed.